1. Field of the Invention
The present invention relates to a reinforcement structure of a pipe which is suitable for fixing a reinforcement member such as a resin material into a pipe.
2. Description of the Related Art
As a structure for reinforcing a closed sectional structure, for example, there have been known (1) a structure having a resin material inserted therein and (2) a structure described in Japanese Patent Unexamined Publication No. Hei.8-2289(JP-A-8-2289) "Instrument Panel Reinforcement and Instrument Panel Reinforcement Manufacturing Method".
The art (1) will be below.
FIG. 15 is an exploded perspective view showing a conventional reinforcement structure of a closed sectional structure.
A center pillar 100 to be the closed sectional structure serves to interpose a stiffener 103 between an inner panel 101 and an outer panel 102. In order to reinforce the center pillar 100, a resin material 104 for reinforcement is provided between the inner panel 101 and the stiffener 103. The reference numerals 105 and 105 denote a fixing hole for fixing the resin material 104 to the inner panel 101.
FIG. 16 is a sectional view showing a conventional center pillar. The resin material 104 is constituted by a hard resin 106 to be a core member and a foaming resin material 107 fixed to an external surface of the hard resin 106, and clip portions 108 and 108 are provided on the hard resin 106 and are coupled to the fixing holes 105 and 105 of the inner panel 101. Consequently, the resin material 104 is fixed into the center pillar 100.
FIG. 17 is a view illustrating a state in which the conventional center pillar is reinforced. In this state, the foaming resin material 107 (see FIG. 16) is foamed and a foaming resin 111 is filled between the inner panel 101 and the stiffener 103.
Moreover, the art (2) has described an instrument panel reinforcement 10 in which flanges 20, 22, 24 and 26 protruded from an external surface are provided in a pipe-shaped large diameter portion 14, a pipe-shaped small diameter portion 16 is inserted into the large diameter portion 14 and the large diameter portion 14 and the small diameter portion 16 are welded through welding holes 36 and 38 opened on the large diameter portion 14 in order to enhance a strength of an instrument panel of an automobile as shown in FIG. 2.
In the art (1), the resin material 104 can be fixed into the center pillar 100 comparatively easily. In the case in which the art (1) is to be applied to the art (2), the clip portion for fixing a resin material into a fixing hole opened on the small diameter portion 16 requires a special shape, for example. Consequently, a cost is increased. Furthermore, in the case in which the pipe-shaped small diameter portion 16 is elongated, the clip portion for the resin material which is inserted into the small diameter portion 16 should be aligned with the fixing hole in the small diameter portion 16 at an end of the small diameter portion 16. Therefore, a fixing work is hard to perform.